Hydraulic actuator



.. 4z Y 44 es 5' E April 12, 1966 B. D. ROBERTS 3,245,271

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6535 BRUCE D. ROBERTS BY 6l 70 /l `\l se Mfr@ ELT 64 75 68 62 40ATTORNEYS April 12, 1966 B. D. RoBERTs 3,245,271

HYDRAULIC ACTUATOR Original Filed-Jan. 8, 1962 2 Sheets-Shee't 2 8OINVENTOR. v

BRUCE D. ROBERTS ATTOR NEYS United States Patent O 3,245.271 HYDRAULICACTUATOR Bruce I). Roberts, Central States Tooling Service Inc., 35 S.St. Clair St., Dayton, Ohio Griginal application Jan. 8, 1962, Ser. No.164,896. Divided and this application Aug. 19, 1964, Ser. No.

s claims. (ci. 74-1o9) It is a primary objector of this invention toprovide a remotely controlled hydraulic actuator characterized by itsease of connection and removal to a shaft.

A further object of this invention is to provide a hydraulic actuatorwhich is mounted and supported directly on the shaft which is to becontrolled.

A further object of this invention is to provide a remotely controlledhydraulic actuator having an output gear capsule which contains aninternal arrangement for locking the actuator to a splined shaft and forpreventing backlash at such connection.

A still further object of this invention is to provide a hydraulicactuator including a two-way piston motor which includes an automaticinternal bleed characterized by the absence of external bleed valves andpassageways.

A still further object of this invention is to provide a hydraulicactuator as outlined in the preceding object wherein the bleed valvearrangement is carried wholly within the piston member.

Another object of this invention is to provide a remotely controlledhydraulic actuator having an output gear capsule which is particularlyadapted for the di-rect mounting on the splined end of a governor inputshaft.

Other objects and advantages of the invention will be apparent from thefollowing description, the accompanying drawings and the appendedclaims.

In the drawings- FIG. 1 is a diagram of a typical installation of theactuator of this invention on a jet engine in a test cell showing theactuator in elevation;

FIG. 2 is an elevational view of the back of the actuator;

FIG. 3 is a transverse section through the actuator;

FIG. 4 is a fragmentary sectional detail of FIG. 3;

FIG. 5 is a vertical section taken generally along the line 5-5 of FIG.3;

FIG. 6 is a fragmentary section taken generally along the line 6 6 ofFIG. 3;

FIG. 7 is an end view looking into the interior of the gear capsule ofFIGS. 3 and 5 with the gear capsule cover removed and with the buttertiyand operato-r removed, showing the open position of the locking cams;

FIG. 8 is a view similar to FIG. 7 showing the antibacklash buttery inposition with the fingers of the operator being shown in section;

FIG. 9 is an other view similar to FIG. 7, with the butterfly removed,showing the position of the fingers and locking cams when the gearcapsule is locked on the shaft;

FIG. 10 is a perspective view of the butterfly;

FIG. 11 is a transverse section through the butterfly showing the mannerin which it is mounted for limited angular anti-backlash movement on thepins; and

Patented Apr. 12, 1956 "ice FIG. 12 is a perspective view of theoperator.

Referring to the drawings, which illustrate a preferred embodiment ofthis invention, a fragment of a jet engine is shown at 10 in FIG. 1 ashaving a throttle control governor 12 mounted thereon. A remotelycontrolled throttle actuator constructed according to this invention isshown at 15 as being mounted on the shaft of the governor 12. Theactuator 15 is remotely controlled by a sensing unit 16 through whichthe governor input shaft may be accurately positioned in accordance withthe position of the handle 17.

The transmitting unit 16 may consist of any suitable type of hydraulictransmitter, such as the part number 13864 of Adel Precision ProductsCorporation, Burbank, California, and forms no part of the presentinvention. The sending unit 16 and the actuator 15 form a closed looppressurized hydraulic circuit with the hydraulic lines 18 and 19completing the circuit therebetween.

The actuator 15 also preferably includes provision for remote recordingor position indicating, such as an electrical position sender or selsynunit 20 on the actuator 15 which is connected to a remote positionindicating unit 21 through electrical leads 23.

Referring now in detail to the construction of the actuator 15, andreferring to FIGS. 1-3, the major portion of the actuator consists of ablock or body 25 which may be formed of aluminum and which providessupport for the other members of the actuator. The body 25 is formedwith opposite machined planar faces and a generally cylindrical cavity26 within which is received an output gear capsule indicated generallyat Z8 in FIG. 3.

The capsule 28 is supported for rotation within the body 25 between apair of opposite cast covers or bearing housings. The front housing 30is seen in FIG. l and also provides support for the sending unit 26. Therear housing 31 is annular in shape and is shown in FIG. 2 as beingmounted on the back or rear surface of the body 25. The front and rearplates are shown in section in FIG. 5 where it may be seen that thefront plate 30 is formed with an annular shoulder 35 within which a race36 of ball bearings is received. Similarly, the back plate 31 isshouldered at 38 and also receives another race of bearings 39. The gearcapsule 2S is mounted between the covers for rotation in the bearings 36and 39.

The body 25 also is formed with a longitudinal bore which intersects thecavity 26. A cylinder liner 40 is received within the longitudinal boreand extends outwardly from each end thereof, and forms a hydrauliccylinder. The opposite ends of the cylinder liner 40 are closed by leftand right cylinder head blocks 42 and 43 which are recessed to receivethe liner 40. 'I'he cylinder head blocks are respectively secured tomating outer surfaces of the body 25 by machine screws 44 and 45. Theright-hand block 43 also includes a pair of arms 48 which form a pivotalconnection to a radius rod Sil by means of which the actuator may besecured against rotation relative to the governor 12.

The cylinder blocks 42 and 43 form closures for the extended ends of thecylinder liner 40 and form a seal with the body 25 and with the liner40. Each of the blocks 42 and 43 define hydraulic fluid inletpassageways 51 and 51 communicating with the ends of the liner throughthe respective blocks and terminating at inlet connections 52 and 53,shown in FIG. 1.

A two-way hydraulic piston 55 is received for axial movement within theliner 4t). The piston 55 is formed in two parts including a main pistonportion 56 which has a rack 58 formed thereon in engagement with theteeth of the gear capsule 28. The piston 55 includes a secondary or amovable piston portion 6i) formed with a head 61 and an extending stem62 slidably received within a suitable axial opening or bore 63 formedin the main portion 56. Each end of the piston is formed with a recessto accommodate a V-cup ring 64 providing a seal with the liner 4i) andisolating the ends of the piston, forming separate hydraulic chambers 65and 66 at the opposite ends thereof.

The two portions and 56 of the piston 55 form a valve which, is normallyclosed during operation, as shown in FIG. 3, but which is open when thehydraulic system is depressurized to provide communication through thepiston 55 between the chambers 65 and 66 for the purpose of bleeding theactuator 15. A passageway 67 is formed through the right-hand portion ofthe piston 55 and communicates into the interior of the bore 63.

The bore 63 is formed with a step at 68 which forms a valve with theO-ring 69 on the stem 62. A spring 79 is interposed in the bore 63 andarranged to bias the piston portion 66 outwardly. This provides foriiuid flow in either direction desired between the cavities and 66through a hole 71 drilled through the piston portion 6i) and crossdrilled holes 72 opening behind the ring 69. An O-ring 74 is also formedon the stem to prevent escape of the fluid therepast.

When the hydraulic system is pressurized after bleeding there is agreater area of the piston portion 69 exposed to the chamber 65 thanthere is exposed to the bore 63. Accordingly, a differential force isdeveloped which closes the separate members of the piston 55 togetherthereby sealing the piston after which it acts as a single piston. A setscrew 75 cooperates with a groove 76 to limit the movement of theportion 69.

The gear capsule 28 includes special locking and antibacklash provisionswhereby the entire actuator 15 may be readily connected and disconnectedfrom the splined shaft of a controller 12. Such a spline shaft isindicated at 89 in FIG. 5 and includes two axially aligned splinedportions 81 and 82 separated by a radius S3. Governor input or controlshafts are commonly formed with such an inner spline 81 and outer spline82 to provide for the conventional locking of a split coupling thereonwhich commonly include a transverse rocking bolt received in the radius83. This invention provides an improved coupling forming a part of theoutput gear of the actuator and includes quick disconnectable lockingmeans connectable directly to such a shaft as well as internal automaticanti-backlash.

The rack 58 of the piston 55 is in continuous engagement with theperipheral teeth on a cup-shaped output gear 85 forming the main portionof the capsule 23. The gear 85 is rotatably received within the bearing39 and supports a spring retainer cap 8S which is, in turn, rotatablyreceived within the bearing 36. The cap S3 is secured to the gear 85 bymeans of a plurality of machine screws 89.

The views of the capsule comprising FIGS. 7-9 are looking into theinterior of the gear 85 with the spring retainer cap 88 removed. Thegear S5 includes a spline connection at 90 (FIG. 5) which is arrangedand proportioned to engage the inner spline portion S1 of the shaft 89.A pair of pins 92 and 93 extend in a generally axial direction from theback wall of the gear 85 and are arranged in diametrically opposed 180locations on opposite sides of the spline portion 90.

The pins 92 and 93 pivotally support a pair of locking arms or cams 95and 96 which may be of identical construction to each other, as bestshown in FIGS. 7 and 9, wherein they are shown respectively in aretracted position clear of the shaft S0. The cams are movable to aninner position in engagement with the radius 83 of the shaft, as shownin FIG. 9. The cams 95 and 96 comprise the spline locking means whichare movable inwardly into locking engagement with the shaft 80 at theradius 83 and prevent the withdrawal of the shaft from the actuator 15and the withdrawal of the actuator 15 from the controller 12.

A generally key-shaped spline-locking butterfly is also mounted on thepins 92 and 93 in superimposed relation over the cams 95 and 96, asshown in FIG. 8. The buttertiy 100 consists of a backlash-removingmember and is formed with an internal spline 101 which is axiallyaligned for engagement with the outer spline portion S2 of the shaft 80when the spline portion 90 of the gear 85 is engaged with the innerspline portion 81,

The pins 92 and 93 extend into aligned openings 105 formed in thebutterfly 100. These openings are of slightly greater diameter than thecooperating pins which provides for limited angular locking movement ofthe buttertiy 100 as indicated at 106 in FIG. 11.

The locking of the butterfly 160 on the spline portion 82 is effected bythe lingers 110 of an operator 112. The operator 112 is mounted forrotation within the capsule 28 with the ngers 110 extending inwardly asshown in FIG. 5. These fingers operate within opposite 45 radialrecesses 113 formed in the opposite sides of the butterfiy 160 and alsooperate around the outer circumference of the cams 95 and 96 and serveto move the cams inwardly with clockwise rotation of the operator. Asshown in FIG. 9, the fingers and the cams 95 and 96 do not form aninterference fit but the ingers are free to move past the curve backsurfaces of the earns until they come into engagement with the abutments114 of the butterfly 109. In this manner, the fingers 110 can effect thelimited anti-backlash rotation of the butteriiy 161) on the pins 92 and93.

The locking position of the cams 95 and 96 and the clockwise or backlasheliminating position of the buttertiy 160 is maintained by an internalanti-backlash coil spring 115. The spring 115 is received over the stem118 of the operator 112 and has one end engaged in a recess in the backof the operator and has the opposite end engaged within a suitablerecess formed within the cap 88. The spring 115 is wound in tension andtends to rotate the fingers 110 of the operator 112 in the clockwisesense.

The stem 118 of the operator 112 extends through an opening 116 formedwithin the cap 88 and is supported for rotation at this opening. Thestern 11S is formed with an internal driving hex 126 which is accessiblethrough an access opening 121 lformed in the plate 30. Any suitabletool, such as the tool 125 having a hexagonal head 126, may be insertedinto the stem of the operator 112 to rotate the operator in thecounterclockwise sense against the force of the spring 115.

The operation of the mechanism within the gear capsule 28 will bedescribed first since it is employed first in the engagement and removalof the actuator from a suitable splined shaft on a controller. Asuitable tool, such as the tool 125, is inserted into the operator 112and the operator is rotated in the counterclockwise sense and held inthis position while the actuator 15 is positioned on the shaft, such asthe shaft S0. In this position of the operator 112, the cams 95 and 96are free to rnove outwardly into the position shown in FIGS. 7 and 8.The inner beveled edges of the cams provide their outward movement whenthe shaft 80 is inserted.

The shaft 80 is inserted until the end of the shaft bottoms on the innersurface of the operator 112. At this position, the spline portion 90 ofthe drive gear 85 is positioned on the inner spline section 81 of thegear 80, and the anti-backlash butterfly 100, which has its splinesection 101 in alignment therewith, is engaged on the outer splinesection 82 of the shaft.

The tool 125 is then released, and the spring 115 rotates the operator112 and the fingers 110 in the clockwise sense. This movement firstoperates against the curved backs of the locking cams and moves the camsinwardly into engagement with the radius 83, as shown 93, it is biasedin an anti-#backlash sense on the shaft 80.

The position of the fingers at this time is also shown in FIG. 9, andthey form a lock against the outward or releasing movement of the cams95 and 96, thereby locking the gear capsule 28 and the actuator 15 onthe shaft in driving yrelation to the shaft 80. The radius rod 50 maythen be connected to prevent the relative rotation of the actuator 15.

The hydraulic connections may then be made at 52 and 53 to the endblocks 42 and 43. It is necessary to purge the actuator of all air whichmay be entrapped therein, so that the piston 55 faithfully andaccurately follows the position of the handle E17. This inventionincludes a simplified bleed arrangement by means of which `all of theair within the hyd-raulic portion of the actuator may be completelypurged and removed. Any suitable pumping mechanism may be employedwithin the hydraulic lines 18 and 19 to pump uid through the actuator atsubstantially zero pressure, and then to cause the pressurization of theclosed hydraulic circuit. One satisfactory such mechanism consists of acompensator which is sold as part number 15915 of Adel PrecisionProducts Corporation, a-bove, and forms no part of the presentinvention.

Purging fluid is caused to oW in either direction through the actuator.For the purpose of illustration, it may be .assumed that the fluidenters through the inlet connection 52 and leaves through the connection53. The two parts 60 and 55 of the piston 55 are pushed away from eachother by the spring 70 and the hydraulic fluid ows from the chamber 65,through the axial passageway 71 within the piston portion 60, throughthe T passageway 72, and into the interior of the hollow piston member56 and out the axial passageway 67 into the right-hand chamber 66 forliow through the passageway 51. In this manner, al1 of the ent-rappedair may be effectively purged.

The hydraulic system is then pressurized by a suitable compensator unitsuch as described above in the manner well known in the art. The member60 has a greater area exposed to the chamber y65 than Vit does to theinterior of the piston member 55. During pressurization, the member 60will be forced lagainst the spring 70 to the right into the closedposition shown in FIG. 3 which has the effect of seating the O-ring 69in the bore 63. In this closed position, each end of the .piston 55 isisolated from the other, and the parts of the piston move as a un1t.

The movement of the handle 17 is translated into `an equivalent movementof the piston 55 within the cylinder liner 40. Preferably, the piston 55is formed with a clearance t within the liner 40 and the pressurizationcauses the expansion of the V-block rings 64 therelby tending to holdthe rack 58 into engagement with the piece of the output gear 85.

The position of movement may be indicated by a position indicatingsystem including a sending 'unit 20 (FIG. 6) which is geared in drivenengagement with the drive gear 85 through an anti-backlash gear 130. Theunit 20 provides electrical position reference for the positionindicator 21 within the control room. The anti-backlash gear 130 isfully described in applicants copending application Serial No. 104,435,led April 20, 1961, now Patent No. 3,153,989, and forms no part of thisinvention.

It .is therefore seen that this invention provides an actuator which maybe readily attached and removed from the shaft of a jet engine throttlecontroller, and requires no other connection to the controller with theexception of the radius rod 50 which may make any suitable connection toprevent the rotation of the unit. In other words, the actuator 15 istotally wholly supported on the shaft which it actuates and positions.The actuator not only includes a gear capsule which provides convenientconnection and disconnection to the shaft, but also provides `anIanti-backlash connection.

As a matter of further convenience and simplification, the hydraulicpiston is formed in two parts which are biased apart by a spring,forming a valve and which move together when the unit is pressurizedfor subsequent operation. In the biased apart position, the two pistonmembers lcomplete an internal piston passageway for the purging of theactuator of `all entrapped air. Thus, all external bleed lines andvalves are eliminated in this invention.

While the form of -apparatus herein described constitutes a preferredembodiment of the invention, it is to be understood that this inventionis not limited to this precise form of apparatus, and that changes maybe made therein without departing from the scope of the invention whichis defined in the appended claims.

What is claimed is:

1. A hydraulic throttle actuator for positioning the splined rotatableshaft of a throttle and adapted for mounting directly on such shaft,comprising a body, a cylinder in said body, a two-way piston received insaid cylinder and positionable axially therein in accordance with adesired throttle position, a rack gear on said piston, an output gearrotatably received in said body in driven relation to said rack gear andhaving means therein forming a spline connection arranged for directmounting on such shaft in driving relation thereto and supporting saidactuator thereon, a separate spline engaging backlash removing memberhaving a spline portion axially aligned with said gear spline connectionand movable angularly with respect to said output gear and alsoengageable with the spline shaft in axially spaced relation to saidspline connection of said gear, and an externally accessible operatorrotatably mounted on said output gear in axially aligned relationthereto having means thereon movable into engagement with said backlashremoving member to urge said member in said angular sense for lockingsaid actuator on said shaft, and spring means urging said operator intosaid engagement with said member.

2. A hydraulic throttle actuator for positioning the splined rotatableshaft of a throttle and adapted for mounting directly on said shaft,comprising a body, a cylinder in said body, a two-way piston received insaid cylinder and positionable axially therein in accordance with adesired throttle position, a rack gear on said piston, an output gearcapsule rotatably received in said body including an Voutput gear indriven relation to said rack gear and having means thereon forming aspline connection arranged for direct mounting on such shaft in drivingrelation thereto and supporting said actuator thereon, a separate splineengaging backlash removing member in said capsule having a splineportion axially aligned with said gear spline connection and movableangularly with respect to said output gear and also engageable with thespline shaft, a capsule cap enclosing said member and secured to saidoutput gear, and an externally accessible operator rotatably mounted insaid cap in axially aligned relation to s-aid output gear having meansthereon movable into engagement with said backlash removing member tourge said member in said angular sense for locking said actuator on saidshaft, and a coil spring in said capsule between said cap and saidoperator and connected to urge said operator into said engagement withsaid members.

3. An actuator adapted for simplified connection to and removal from asplined shaft and for support on such shaft wherein the shaft includestwo axially aligned splined portions divided by a radius groovecomprising, a body, power means in said body movable into selectedpositions, an output gear rotatably mounted in said body in drivenrelation with said power means, said gear being generally cup-shaped andhaving an internally splined portion adapted to receive said shaft onthe inner spline portion thereof, a backlash removing spline memberreceived within the cup of said gear and engageable with said outerspline portion of said shaft, a movable locking cam positioned in thecup of said gear between said spline portion and said member and mountedon said gear for movement between an outer position clear of the shaftand an inner position engageable with said radius groove, and a springbiased operator mounted on said gear having a finger thereon engageablewith the member to urge said member angularly into blacklash eliminatingengagement with such shaft and further engageable with said cam to movesaid cam into its inner position and preventing movement thereof intosaid outer position.

4. A hydraulic actuator adapted for direct connection to a driven shaftwhich has inner and outer spline portions separated by a radius groove,comprising an output shaft in said actuator having means thereon forminga driving spline connection engagable with such driven shaft at saidinner spline portion, a separate backlashremoving member having a splineconnection formed thereon and being axially aligned with said drivingspline and engagable with such driven shaft at the outer spline portionthereof, means mounting said member for limited angular movement withrespect to said output shaft, an operator mounted for angular movementwith respect to said output shaft between an operative position inengagement with said member urging said member angularly with respect tosaid output shaft into backlash removing engagement with the outerspline portion of the driven shaft and also being movable out ofengagement with said member into a retracted position, spring meansurging said operator into said operative position with said member, alocking cam having an inner surface engageable with the driven shaft atsuch groove, means mounting said locking cam for movement between aretracted position clear of the driven shaft and an inner position inwhich said surface thereof is received in the shaft groove, and means onsaid operator engageable with said cam in the retracted positions ofsaid oper- 40 ator and said cam to move said cam into said innerposition thereof concurrently with the engagement of said operator withsaid backlash removing member.

5. A hydraulic throttle actuator for positioning a splined rotatableshaft of `a throttle in which the splined shaft is formed with a radiusfor facilitating attachment of a driven shaft thereto, comprising abody, a cylinder in said body, a piston received in said cylinder andpositionable axially therein in accordance with a desired throttleposition, a rack gear on said piston, an output gear rotatably receivedin said body in driven relation to said rack gear and having meansthereon forming a spline connection adapted for mounting on such shaftin driven relation thereto and for supporting said actuator thereon, aseparate spline-engaging backlash-removing member having a splineconnection portion engagable with the spline shaft in axially spacedrelation to said spline connection of said output gear thereon, meansmounting said member for angular movement with respect to said outputgear, a pair of arcuately shaped locking cams positioned generally onopposite sides of such shaft, means on said gear pivotally mounting saidcams in opposed relation to each other for movement between a retractedposition radialy clear of such shaft and an inner position in engagementwith the shaft radius, and an operator rotatably mounted on said gearand having means thereon movable into engagement with said locking camsand said backlash-removing member urging said cams inwardly into saidinner position thereof and urging said member in an angular sense foreliminating backlash between said ouput gear and said throttle shaft.

References Cited by the Examiner UNITED STATES PATENTS 1,474,153 11/1923Klein 287-53 1,828,305 10/1931 Zeder et al 74-440 X 2,250,369 7/1941Gorton 74--440 X 3,040,717 6/1962 Rumsey 74-91 X 3,090,641 5/1963Eminger 74-440 X FOREIGN PATENTS 1,199,375 12/ 1959 France.

BROUGHTON G. DURHAM, Primary Examiner.

1. A HYDRAULIC THROTTLE ACTUATOR FOR POSITIONING THE SPLINED ROTATABLESHAFT OF A THROTTLE AND ADAPTED FOR MOUNTING DIRECTLY ON SUCH SHAFT,COMPRISING A BODY, A CYLINDER IN SAID BODY, A TWO-WAY PISTON RECEIVED INSAID CYLINDER AND POSITIONABLE AXIALLY THEREIN IN ACCORDANCE WITH ADESIRED THROTTLE POSITION, A RACK GEAR ON SAID PISTON, AN OUTPUT GEARROTATABLY RECEIVED IN SAID BODY IN DRIVEN RELATION TO SAID RACK GEAR ADHAVING MEANS THEREIN FORMING A SPLINE CONNECTION ARRANGED FOR DIRECTMOUNTING ON SUCH SHAFT IN DRIVING RELATION THERETO AND SUPPORTING SAIDACTUATOR THEREON, A SEPARATE SPLINE ENGAGING BACKLASH REMOVING MEMBERHAVING A SPLINE PORTION AXIALLY ALIGNED WITH SAID GEAR SPLINE CONNECTIONAND MOVABLE ANGULARLY WITH RESPECT TO SAID OUTPUT GEAR AND